If indoors I have no clue. If you're outdoors in the ground or containers try this. Get a gallon water jug and punch a hole or two in the bottom with a small finishing nail. Set it out on a well soaked patch of lawn or whatever. See how long it takes to drain out. Then increase the holes or decrease to get it to last several days. Then place it near the stalk of your plant. It should at least help them for a bit. I've also soaked a bath towel and covered the area around the stalk to slow the soil from drying out. Cover the towel with a split open trash bag to further slow the evaporation. I've done both and took 9 day trips to Hawaii in August (super hot at my place) and saved my gals. A few drooping fan leaves, but they were going to come off anyways. Enjoy your vacation and forget about em, and water when you get back. It is what it is.